1. Filed of the Invention
The present invention relates generally to a cartridge for accommodating a recording medium taking a disk-like shape and a member for cleaning, etc. and a manufacturing method thereof, and more particularly to an improvement of a shutter provided in the cartridge and a manufacturing method thereof.
2. Description of the Prior Art
A recording medium cartridge such as a mini disk cartridge (MD) accommodating a recording medium has a rectangular storage case in which a recording medium having a disk-like shape or the like is encased. The storage case is formed with an opening for inserting a head when in recording/reproducing processes, and a shutter for provided for opening and closing this opening. FIGS. 5A and 5B show an example of a prior art MD cartridge-oriented shutter. FIG. 5A is a top view of the shutter, wherein an upper plate 102a and a lower plate 102b of the shutter 102 are disposed so that the storage case of the mini disk cartridge is sandwiched in between the upper and lower plates 102a, 102b in a vertical direction on the drawing. FIG. 5B is a sectional view thereof. As illustrated in FIG. 5B, a top plate 103 for connecting the upper and lower plates 102a, 102b is formed with a rectangular opening 100 through which to insert a shutter opening/closing member of the apparatus in order to drive the shutter 102 open and shut. A side end surface 101 of the opening 100 is normally formed by a punch-out work and therefore has a cut surface.
Stainless steel has hitherto been used for composing the above-described shutter, however, it can be considered that, for example, an aluminum material is used as disclosed in Japanese Patent Application Laid-Open No.6-346178. What is proposed in this publication is that a resinous layer is provided on the surface of an aluminum alloy in order to enhance a strength, an anti-corrosion and a sliding property etc.
The aluminum material has, if used, an advantage of being capable of reducing both a weight and a cost of the cartridge on the other hand, and has, because of its hardness being small, the following problem. This problem is explained referring to FIG. 6. A shutter opening/closing member 105 moves in a direction b as indicated by the solid line in FIG. 6 in order to drive the shutter 102 so as to open and close the shutter 102, and, with an approach to an opening 100 of a shutter 102, rotates in a direction a, and its tip portion 105a enters the opening 100 as indicated by the broken line in FIG. 6. At this time, the tip 105a of the shutter opening/closing member, 105 impinges upon a side end surface 101 to cause a frictional force. The aluminum material is lower in terms of the hardness than the stainless steel, and, the side end surface 101 being formed as a cut surface by a punch-out work, the side end surface 101 might be chipped by the shutter opening/closing member 105 sliding on the tip 105a. The quantity of the chip of the side end surface 101 becomes larger with more repetitions of the opening/closing operations of the shutter 102. Metal powders caused by the chips are hard to be discharged from the cartridge and an apparatus as well, which might induce inconveniences (such as a sound skip and a drop-out attributed to a damage to the disk) when in recording/ reproducing processes. Consequently, there might also arise a possibility of exerting an adverse influence.
Even in the case of using the aluminum alloy provided with the resinous layer as disclosed in Japanese Patent Application Laid-Open No.6-346178, the opening 100 is formed after providing the resinous layer, and hence the inner side peripheral end surface of the opening is chipped as it used to be because of no resinous layer provided thereon.
Further, as indicated by the solid line in FIG. 6, the shutter opening/closing member 105 is driven for driving the shutter 102 so as to open and close the shutter 102, and moves in an arrow direction b toward the opening 100 while contacting a surface 103a of a top plate 103 of the shutter 102 in an area D indicted by the broken line in FIG. 5A. With this movement, the tip 105a of the shutter opening/closing member 105 causes a frictional force against the surface 103a of the top plate 103 in the area D, and further impinges upon the side end surface 101 of the opening 100 enough to cause the frictional force. The shutter opening/closing member 105 reciprocates in the direction b in FIG. 6 and in a reverse direction bxe2x80x2 thereto, and, with the aluminum material being less in its hardness than the stainless steel with the shutter opening/closing member 105 repeatedly sliding on the surface 103a, the surface 103a of the top plate 103 might be chipped in the area D. A quantity of the chip of the surface 103 and the like becomes larger with a greater number of repetitions of the opening/closing operation of the shutter 102, and there might be a possibility in which the metal powders caused by the chips thereof induce the drop-out or the like when in the recording/reproducing processes as in the case described above.
On the other hand, Japanese Patent Application Laid-Open No.8-3061155 discloses that a shutter composed of an aluminum alloy is coated with a layer for preventing a polyethylene film from being adhered to the shutter. Further, Japanese Patent Application Laid-Open No.5-41055 discloses that the surface of the stainless steel shutter is provided with a protective resinous layer for preventing a damage and adhesions of a fingerprint and an oil film.
Japanese Patent Application Laid-Open No. 8-306155 in which the layer is coated for preventing the adhesion of the materials accommodated therein to the cartridge, however, neither deals with the problem of the chip nor discloses any measures against the chip caused by the sliding of the shutter opening/closing member of the apparatus. Moreover, Japanese Patent Application Laid-Open No. 5-41055, in which the protective resinous layer for preventing a damage to the shutter is provided, is intended to cope with a friction of the shutter which occurs by accident when cases are stacked, but does not disclose any measure against the chip enough to the problem of the chip due to the slide of the shutter opening/closing member of the apparatus.
It is a primary object of the present invention to provide a cartridge and a manufacturing method thereof that are capable of preventing a chip in a hole of a shutter into which a shutter opening/closing member of an apparatus enters even when the shutter is composed of a light metal material having low hardness such as aluminum and the like.
It is another object of the present invention to provide a cartridge capable of reducing a chip on a shutter surface which is caused by repetitive sliding actions between the shutter and the shutter opening/closing member of the apparatus even when the shutter of composed of the light metal material having the low hardness such as aluminum or the like.
To accomplish the above objects, according to one aspect of the invention, a cartridge for accommodating a tape-like member or a disk-like member, is provided with a case, an opening formed in the case, a shutter for opening and closing the opening, and a hole, formed in a surface of the shutter, with which an external drive member engages to drive the shutter, wherein the inner side peripheral surface of the hole, with which at least the drive member comes in contact when opening and closing the opening, is formed of a continuous surface continuous from the shutter surface.
According to the cartridge described above, when the drive member, for driving the shutter of the external apparatus and the like engages with the hole of the shutter, the inner side peripheral surface of the hole upon which the drive member impinges is the continuous surface continuous from the shutter surface but is not a cut surface as in the prior art, and hence the quantity of the chip can be decreased. Magnetic recording mediums of a magnetic type, an optical type and an magneto-optic type and the like, and a member for cleaning may be each exemplified as the tape-like member or the disk-like member accommodated in the cartridge. With those accommodated therein, the recording medium cartridge and the cleaning member can be each constructed.
The continuous surface is formed in a curved shape in the vicinity of the shutter surface, thereby enlarging a contact area of this curved portion with the drive member. The continuous surface has no angular portion upon which the drive member impinges, and therefore a slide resistance between the curved portion and the drive member decreases, whereby the quantity of the chip on the inner side peripheral surface of the hole can be largely reduced.
The shutter includes a pair of flat plates positioned respectively on both surfaces of the cartridge, and a connection plate for connecting the flat plates, and the connection plate may be provided with the hole.
The hole may be formed in a rectangular shape. In this case, a pair of the continuous surfaces may be provided on the inner side peripheral surfaces, facing to each other, of the rectangular hole. With this contrivance, even if the drive member impinges on any one of the face-to-face inner side peripheral surfaces of the hole, the same effect as the above can be exhibited. The continuous surface may be provided on two other surfaces facing to each other, and totally two pairs of the surfaces may also be provided.
The continuous surface may be formed by its being bent from the shutter surface. This bending facilitates the formation of the continuous surface, and the continuous surface may be formed in a curved shape in the vicinity of the shutter surface. Further, when one or two pairs of the continuous surfaces are provided in the face-to-face relationship, these continuous surfaces can be formed by the bending process.
A bending angle of the continuous surface is over 90 degrees to the shutter surface, whereby the drive member becomes hard to impinge upon the side end of the inner side peripheral surface of the underside of the shutter. The problem of the chip caused by the drive member does not occur at this side end.
The shutter may be composed of a light metal material. The above-described construction of the shutter obviates the problem of the chip on the inner side peripheral surface of the hole, and therefore the chip can be restrained even if composed of the light metal material having the low hardness. It is therefore feasible to reduce both the weight and the cost of the cartridge by the shutter being composed of the light metal material. Aluminum (Al), magnesium (Mg), titanium (Ti), beryllium (Be), and light metal materials such as alloys of these metals may be each exemplified as the light metal material.
According to another of the invention, there is provided a method of manufacturing a cartridge, for accommodating a tape-like member or a disk-like member, constructed of a case, an opening formed in the case, a shutter for opening and closing the opening, and a hole, formed in a surface of the shutter, with which an external drive member engages to drive the shutter, an inner side peripheral surface of the hole, with which at least the drive member comes in contact when opening and closing the opening, formed of a continuous surface continuous from the shutter surface. This method includes the steps of forming a starting hole with a portion corresponding to the continuous surface being left in a punch-out work for forming the hole of the shutter, and forming the hole by bending the portion corresponding to the continuous surface.
According to the manufacturing method described above, the starting hole is formed with the portion corresponding to the continuous surface being left. Next, the portion, corresponding to the continuous surface, of the starting hole is bent, whereby the above continuous surface can be formed on the inner side peripheral surface of the hole of the shutter. The continuous surface can be thereby formed in the hole by the simple steps.
The hole may be rectangular, the portion corresponding to the continuous surface may be provided on each of two sides facing to each other, and the portions corresponding to the continuous surface may be bent on the two sides. With this configuration, a bending force is preferably applied to the material with a well force balance when the hole is subjected to a bending work by a die assembly. Further, when the portion corresponding to the continuous surface is provided on each of four sides, and the portions corresponding to the continuous surface may be bent on the four sides.
When punching out the starting hole, the slit portions or punch-out portions may be formed at the side ends of the portion corresponding to the continuous surface, thereby facilitating the bending work in the hole. Further, the shutter material can be prevented from stretched out at a corner of the starting hole, which is believed to be preferable.
The hole may be formed by inserting a die member assuming a configuration corresponding to the configuration of the hole into the starting hole. Further, the shutter may be composed of a light metal material.
According to further aspect of the invention, a cartridge for accommodating a tape-like member or a disk-like member, is provided with a case, an opening formed in the case, a shutter, composed of a light metal material, for opening and closing the opening, and a hole, formed in a surface of the shutter, with which an external drive member engages to drive the shutter, wherein a resinous protection layer having a thickness of more than 12 xcexcm is provided on the surface of the shutter upon which the drive member impinges when engaging with the hole, and contains a lubricating agent within a range of 2 to 10.5% by weight.
According to investigation of the prevent inventors, the resinous protection layer having a thickness more than 12 xcexcm is provided on the surface at which the drive member of the external apparatus impinges upon the shutter, thereby making it feasible to effectively reduce the chip produced with the repetitive sliding actions of the drive member on the shutter surface. It has proven that the effectiveness increases if the thickness is more than 15 xcexcm. A polyester series resin, an epoxy series resin and an acrylic series resin can be used as a resin material of the resinous protection layer, however, the present invention is not limited to those materials. Moreover, the portion of the shutter, provided with the resinous protection layer, may exist within a range where at least the drive member of the apparatus impinges thereon but may be provided in other areas. Further, the magnetic recording mediums of the magnetic type, the optical type and the magneto-optic type and the like, and the member for cleaning may be each exemplified as the tape-like member or the disk-like member accommodated in the cartridge. With those accommodated therein, the recording medium cartridge and the cleaning member can be each constructed.
The resinous protection layer contains 2 to 10.5% lubricating agent by weight, preferably, 3 to 10.5% lubricating agent by weight, thereby improving a sliding property of the drive member on the shutter surface and making is possible it further reduce the chip caused by sliding of the drive member on the shutter surface. If the content quantity of the lubricating agent is less than 2% by weight, a satisfactory sliding property can not be obtained on the resinous protection layer. Further, if over 10.5% by weight, adhesion of the resinous protection layer to the shutter declines and such is therefore easy to exfoliate. In addition, a printing property with respect to the shutter is deteriorated. Note that polyethylene fluoride, silicon and molybdenum disulfide may be each used as a material of the lubricating agent, however, the present invention is confined to these materials.
It is preferable that the thickness of the resinous protection layer on the surface of the shutter for opening and closing the opening be less than 40 xcexcm. The functioning of the resinous protection layer becomes far better as the thickness thereof becomes larger. In terms of a relationship with, e.g., a coating step of the resinous protection layer, however, when forming the resinous protection layer also on the outer surface of the shutter at which to open and close the opening, and if the resinous protection layer becomes too thick, the thickness of the whole shutter increases. It is therefore required that the thickness of the material of the shutter be decreased, and as a result a strength of the shutter decreases. Further for avoiding this decrease, a wall thickness of the case of the cartridge fitted with the shutter must be made small, and the strength of the case decreases. It is therefore desirable that the thickness be less than 40 xcexcm.
It is preferable that the inner side peripheral surface of the hole be constructed of the continuous surface continuous from the shutter surface. In this construction, the inner side peripheral surface of the hole, upon which the drive member impinges, is the continuous surface which is continuous from the shutter surface but is not the cut surface as has hitherto existed, and hence the inner side peripheral surface of the hole is chipped by the slide of the drive member with a difficulty. Then, the quantity of the chip can be reduced.
The continuous surface is formed in the curved shape in the vicinity of the shutter surface, whereby a contact area of the drive member with the curved portion can be enlarged. There is no angular portion upon which the drive member impinges, and therefore the slide resistance of the drive member on the curved portion is decreased, and the quantity of the chip on the inner side peripheral surface of the hole can be largely reduced, which is conceived preferable.
The continuous surface may be so formed as to be bent from the shutter surface. With this bending, the continuous surface can be easily formed, and may be formed with a curved shape in the vicinity of the shutter surface.
The shutter is composed of the light metal material, thereby obviating the problem of a chip on the inner side peripheral surface of the hole as well as on the shutter surface. It is therefore possible to effectively restrain the chip even when composed of the light metal material having the low hardness.
Other features and advantages of the present invention will become readily apparent from the following description taken in conjunction with the accompanying drawings.